Mocha only running one test file

My Mocha tests were working fine, but when I added a new module (and test), mocha stopped running all of my test files and now only runs the single new test.

My test script:

env NODE_PATH=$NODE_PATH:$PWD/src mocha --recursive --compilers js:babel-core/register src/**/*.test.js --require babel-polyfill

My project is structured like this:

/src
  /components
    /component-name
      index.js
      component.js
      component-name.test.js
      style.scss
  /util
    /module-name
      index.js
      module-name.test.js
  /some-other-module
    index.js
    some-other-module.test.js

I had several tests in /components and /util and everything worked fine, but when I place a module into /src (like /some-other-module) with a .test.js file in it, Mocha only runs that test file and none of the others.